The period of time when kittens are learning to eat solid food is called the “teething” or “growth” phase. The kitten will chew on his mother’s nipple, but you can tell by how full he is compared to the size of teat he starts with that this stage has started. Sometimes you can see how big a kitten will grow before it spends its first night away from Mother, which means it could be about 4 months old at this point. You should not attempt to hand-rear young kittens because they may become seriously ill if they do not get proper veterinary care soon after birth. If you are rearing them yourself, make sure your animal shelter knows where your new cat lives so they can locate her for you should she ever stray during your absence (or as soon as possible). Remember: as long as there is no health problem and she eats well and purrs loudly every morning, a cute little baby cat belongs in a home! Check out our article on What Happens After Kittens Leave Their Moms .